Despite everything they say I think Tom Bombadil was unnecessary in a movie that was already too long but perfection. I hope to see him in the new Lord of the Rings series. So my vote goes to Lady Stonehart

Is the character in the photo from GoT a popular or well-known one? I'm wondering if people see her photo, some may just vote for her, regardless of the question (some people, it seems, don't even always read the questions) so perhaps just showing a GoT poster might be safer? Of course, a similar thing could happen there. I know almost nothing about GoT and the novels it comes from so I'm just throwing this out there. You clearly know more so you're the better judge, I'm sure, but I'd imagine it could be a problem. It's too bad that there's no Lady Stoneheart in the GoT video game: that was a good idea for Tom Bombadil.

After writing the above, I saw that the GoT character shown is in 25 episodes so perhaps a less well known character (https://www.imdb.com/title/tt0944947/mediaviewer/rm3049471488?)(?) or maybe just add a brief explanation under the photo (that the image is just a stand-in because, since Stoneheart isn't a character in the series, there's no photo)?

Tom Bombadil. He is a minor but intriguing character, who can hold the Ring without ever being affected by the way it corrupts all of its users. I always wondered what his immunity implied about him.

Lady Stoneheart is far from "The Song of Ice and Fire"'s most complex characters and not someone I would like to see more of. A resurrected/undead/zombified version of Catelyn Tully-Stark who only cares about vengeance. She leads a group of murderous vigilantes in a lynching campaign against the Freys, their allies, and anyone even remotely connected to them (women and children included).

I liked Catelyn as a character, but Stoneheart seems more of a generic horror film villain than a three-dimensional character.